Add tests for SweepIterator. Update applyexp test.

Author: emstoudenmire

test/solvers/test_applyexp.jl

@@ -53,7 +53,7 @@ end
 
         nsites = 2
         factorize_kwargs = (; cutoff, maxdim)
-        E, gs_psi = dmrg(H, psi0; factorize_kwargs, nsites, nsweeps, outputlevel)
+        E, gs_psi = dmrg(H, psi0; factorize_kwargs, nsites, nsweeps, outputlevel = 0)
         (outputlevel >= 1) && println("2-site DMRG energy = ", E)
 
         nsites = 1

test/solvers/test_sweepiterator.jl

@@ -0,0 +1,60 @@
+using Test: @test, @testset
+using ITensorNetworks: ITensorNetworks, AbstractProblem, RegionIterator, SweepIterator, compute!, region_iterator, region_kwargs
+
+include("utilities/tree_graphs.jl")
+
+# TestProblem type for testing
+struct TestProblem <: AbstractProblem
+    graph
+end
+
+ITensorNetworks.state(T::TestProblem) = T.graph
+
+ITensorNetworks.compute!(R::RegionIterator{<:TestProblem}) = "TestProblem Compute"
+
+
+@testset "SweepIterator Basics" begin
+    g = build_tree(; nbranch = 3, nbranch_sites = 3)
+    prob = TestProblem(g)
+
+    nsweeps = 5
+
+    # Basic construction, taking length
+    sweep_iter = SweepIterator(prob, nsweeps)
+    @test length(sweep_iter) == nsweeps
+
+    # Pass keyword parameters
+    test_kwarg_a = 1
+    test_kwarg_b = "b"
+    sweep_iter = SweepIterator(prob, nsweeps; test_kwarg_a, test_kwarg_b)
+    @test region_kwargs(region_iterator(sweep_iter)).test_kwarg_a == test_kwarg_a
+    @test region_kwargs(region_iterator(sweep_iter)).test_kwarg_b == test_kwarg_b
+
+    # Pass array of parameters
+    kws_array = [(; outputlevel = 0), (; outputlevel = 1)]
+    sweep_iter = SweepIterator(prob, kws_array)
+    @test length(sweep_iter) == length(kws_array)
+    @test region_kwargs(region_iterator(sweep_iter)).outputlevel == 0
+end
+
+@testset "SweepIterator Iteration" begin
+    g = build_tree(; nbranch = 3, nbranch_sites = 3)
+    prob = TestProblem(g)
+
+    nsweeps = 5
+    sweep_iter = SweepIterator(prob, nsweeps)
+    count = 0
+    for _ in sweep_iter
+        count += 1
+    end
+    @test count == nsweeps
+
+    # Test case of one iteration
+    nsweeps = 1
+    sweep_iter = SweepIterator(prob, nsweeps)
+    count = 0
+    for _ in sweep_iter
+        count += 1
+    end
+    @test count == nsweeps
+end